1.3.1 Data Collection
This part explains the criteria to choose EAPs and CMs in the current dissertation.
1.3.1.1 Criteria to choose EAPs
Firstly,all the academic papers come from Science Citation Index and Social Sciences Citation Index,ensuring that all the authors are professional.
Secondly,there are totally 240 academic papers.Based on the discussion of Bernstein(1996,1999,2000)and Martin(2011)on knowledge structure,which has been explained in Section 1.1,the papers are chosen from three disciplines:N,S and H,with 80 papers per discipline respectively.At the same time,half number of the papers,i.e,120 of them are written by AEs and the other half by ANE.The article numbers and the specific word numbers of the chosen EAPs are listed in Table 1.1 and Table 1.2 respectively.
Table 1.1 Article numbers of the chosen EAPs
Table 1.2 Word numbers of the chosen EAPs
Seen from Table 1.2,the EAPs in H occupies larger proportion(778,275 words)than the other two disciplines.AEs contribute more words than ANEs in the chosen data.It is notable to state that the frequencies for comparison throughout this dissertation are made with a proportion of per 100,000 words.
1.3.1.2 Criteria to choose CMs
As mentioned above,the CMs analyzed in the dissertation appear in various forms such as conjunctions,conjunctive adverbs,prepositional phrases an so on.However,the current study could not present an exhaustive analysis of all the conjunctive markers.Thus it is necessary to conduct a scientific and necessary choice.
Firstly,the frequency search of the CMs is based on the research of Leech et al.(2001).They(Leech et al.,2001)list words of the English language in British National Corpus(henceforth BNC)and give information about their frequencies in actual use.BNC is a finite,balanced and sampled corpus,which contains a sample of some 100 million words of present-day spoken and written British English.By making use of BNC,Leech et al.(2001:xi)write this word frequency book in using a corpus which is large,varied(100 million words),and more up-todate to provide frequency lists and comparisons between spoken and written English.
According to Leech et al.(2001:294),the frequently used conjunctions(more than ten times per million words)are presented in Table 1.3.
Table 1.3 Conjunctions listed by frequency(per million words)(From Leech et al.,2001:294)
In this dissertation,CMs are restricted to those explicit formal conjunctive resources forming expansive clause complexes.So those CMs connecting words,phrases or projective clause complexes,or informal CMs are out of this research.Thus,the CM &,cos,and that,which are in parenthesis in Table 1.3 are not taken into account.
In this current study,the CMs not only include conjunctions,but also contain adverbs such as however,nevertheless,etc.Based on the study of Leech et al.(2001:291-293),the comparatively frequent adverbs,which also function as conjunctive markers are listed in Table 1.4.
Table 1.4 Conjunctive adverbs listed by frequency(based on Leech et al.,2001:291-293)
Apart from the frequently used conjunctions and adverbs which could function as conjunctive markers,some numerals such as one,two,three and ordinal numbers such as first,second,third could also be concluded in the domain of CMs.The frequencies of these numerals all surpass 100 per million words in the frequency research of Leech et al.(2001).
Finally,there are some prepositional phrases which could function as conjunctive markers.There is no summary about the frequencies of these phrases in Leech(2001).Thus,by analyzing the chosen EAPs manually,this study lists 29 frequently used prepositional phrases:by contrast,on the contrary,in comparison,by comparison,on the other hand,in any case,after all,in fact,in other words,in the same way,by the same token,for this reason,as a result,in the first place,in the second place,for one thing,to begin with,to start with,from the beginning,in conclusion,in sum,to conclude,to sum up,to summarize,in this way,in this regard,in that case,in this sense,and in a different way.
Therefore,in this dissertation,the CMs waiting to be analyzed contains 44 conjunctions,51 conjunctive adverbs,8 numerals(including ordinal numbers)and 29 prepositional phrases,i.e.,132 CMs in total.